Graphical modeling environments enable interactive design, testing, and implementing of a variety of time-varying systems, including communication, control, signal processing, video processing, and image processing systems. A graphical model of a dynamic system can be represented as a collection of blocks interconnected by lines. These lines may represent signals. Blocks represent elements in the dynamic system. Signals represent input values and output values of dynamic systems.
Graphical models may include subsystems. A subsystem may contain a group of blocks, signals, and/or other subsystems, and may be represented in a graphical modeling environment as a single block, producing a layered graphical model. Layered graphical models facilitate design management and simulation by segmenting a graphical model into various components. For example, a layer of a graphical model can be represented by a subsystem, and the contents of the subsystem may include blocks and lines that represent another layer of the graphical model.